Only four months ago President Obama had emerged from a bruising presidential election with a convincing win, buoyed by unexpected gains in Congress and claiming a mandate to push his agenda. The last two weeks have shown how quickly a reversal of fortune can change the tone of politics in Washington.

Following his election, the Republicans were back on their heels, and Obama appeared newly confident, bolstered by the belief that the American people were on his side. He was ready to push his program with new aggressiveness on numerous fronts, and prospects for success on gun control and immigration, among other issues, seemed good.

But it was never going to be easy. Republicans in Congress were ready to exploit any weakness they could find, and now Obama finds himself on the defensive. Politico wrote a story this week headlined “D.C. turns on Obama,” saying it was not just Republicans who were on the offensive. Fellow Democrats and the press also sensed weakness.

The press is frequently criticized for deploying sports metaphors to describe politics, reducing everything to a horse race or a slugging match. But in this season of political fisticuffs, boxing provides a lens as good as any to understand what is happening in Washington.

That’s because politics is about power, and boxing is the sport where opponents most directly seek to exercise power over the other. If Republicans were back on their heels at the beginning of the year, that is a boxing metaphor. But the match was not over just because Obama won the election. In fact, it was just beginning.

The Republicans were never going to let Obama off easy. The election may have weakened them, but their weakness seemed to motivate the fierceness of their counterattack. It has been that way ever since the days of Karl Rove, adviser to George W. Bush, who had limped into office in 2001 in a severely weakened state.

All the Republicans needed to do this year was to find an opening where they could land a punch to disrupt Obama’s rhythm. Then they could go on the attack. That’s what the hearings on Benghazi were about. With the IRS scandal, the GOP found Obama with his guard down, and they let him have it. And he understood he had no choice but to take it.

But that wasn’t all. News that the Justice Department had seized the phone records of The Associated Press in a fishing expedition to plug a leak of doubtful harm alarmed liberals as well as Republicans happy to exploit the administration’s blunder. Also alarmed was the press, which, according to the Politico article has become increasingly jaundiced by the administration’s arrogance. There are times, as during the Clinton administration, when the press feels compelled to show that it can be tough on liberals as well as on conservatives, and the spin in coming months on all manner of stories is not likely to be favorable to Obama.

Increasingly, the spin is going to be that Obama is not in charge of events; they are in charge of him. It is not foreign territory for a president. No president is in charge of events, and all presidents encounter difficulties that put them on the defensive.

For people concerned about actual issues the process can be discouraging. Obama’s agenda includes action on energy, climate change, infrastructure, education, health care — and as far as Republicans are concerned, keeping him off balance is a way to fend off that agenda. That a majority of Americans appear to favor Obama’s agenda means that the Republicans have to be extra tough.

Obama, the constitutional scholar, is not conducting a seminar. He’s in the fight of his life. No one gets to have his way untouched in politics. Everyone has to mix it up, take some punches, bob and weave, marshal his strength and try to land some punches of his own. No one ever really wins either. It is a fight that extends ahead in time as long as history continues to unfold.